Bottom filler



H. BARNETT BOTTOM FILLER July 3, 1934.

Filed OGL. 29, 1950 u. I I:

Patented July 3, 1934 BOTTOM FILLER I 1 "Herbert Barnett, Leicester, England, assignor to United Shoe Machinery Corporation, Paterson,

N. J a corporation of New Jersey Application October 29, 1930, Serial Nb. 491,983

4 Claims.

This invention relates to improvements in shoes and to bottom fillers therefor and is disclosed herein with reference to a cold filler adapted to be applied when in plastic condition to the insole of a shoe and to be spread upon the insole before the outsole is attached.

Inthe manufacture of shoes it is usual to fill the space between an inner and an outer sole and within the margin of the shoe upper by means of a filler which may be a shaped piece of felt, leather-board or the like, but which at the present time is often, and usually in the case of welt shoes, a compound of a solid material (such as cork or the like, granulated, comminuted .or otherwise finely divided) with anadhesive or 9 method fillers and cold method fillers.

125 it is allowed to set again. In the case of the cold method filler the compound, in addition to cork or other solid material, usually comprises an" adhesive or binder in the nature of a rubber solution (i. e. a solution of. solid rubber in a volatile solvent, for example naphtha) so that the compound is normally plasticrand becomes set by the evaporation of the solvent, from the binder, The usual hot method filler involves the use of heatingapparatus and considerable time if char-- ring of the solid material (e. g. cork) is to be prevented and also is liable under the pressure and the heat of ,theofoot'during wear to alter its form or position to an uncomfortable degree (the binder being of the nature of glue), while the si l usual cold method filler by reason of the nature of the solvent used involves the danger of fire and consequently requires precautions which many shoe manufacturers are unwilling to take. On the other hand a filler comprising such a rubili her or rubber-like binder as referred to has the advantage that no auxiliary apparatus is necessary to bring it to a workable condition.

Theoretically an ideal compound shoe bottom filler should have the following qualities:it

5,95 should not require any special precautions in factory storage or use; it should not deteriorate under conditions liable to be met with in ordinary shoe factories; it should be pliable or plastic at ordinary temperatures; it should be easily workable; it should set quickly when put in place In Great Britain November 27, 1929 on the shoe bottom in order not to delay fac tory operations; it should, when set, not be brittle or friable nor likely permanently to alter its form or position to any great extent under the pressure and heat of the foot; it should be sufficiently flexible when set to accommodate itself readily without deterioration to the flexure of the shoe in walking; it should be resilient; it should be substantially waterproof; it should be unaffected by change of climate; it should be odorless; it should be sufficiently adhesive to adhere adequately to the shoe partswhen placed in position; it should be economical in first cost and in cost of application; and it should be such as not to act detrimentally upon the shoe parts. Heretofore, a large number of fillers have been suggested each of which has certain advantages but is lacking to some degree at least in other desirable qualities. 9

It is an object of the invention to provide an improved shoe bottom filler having so fas as is possible the qualities of the theoretical ideal referred to above.

In one-of its aspects the invention provides a compound shoe bottom filler which comprises a binder of rubber latex adhesive, that is, an adhesive that includes a substantial amount of rubber in the form of latex, together with suitable comminuted solid material, for example cork. Rubber latex adhesives have various forms, being sometimes merely a natural latex of one or more closely allied varieties of rubber (such as hevea) with the mere addition of a coagulation preventative. Such an adhesive is represented by many of those known commerciale ly as rubber latex. In other cases other materials are added in greater or lesser proportions, for example with the object of modifying the normal setting or the adhesive qualities of the adhesive.

In order to increase the adhesive qualities of the latex bottom filler so that it will stick more firmly to the shoe bottom when it is first applied and before it has had time to set or solidify, a suitable resin, for example in the form of a soap made by treating rosin with concentrated ammonia, may be added to the latex before the latex is mixed with the cork. The addition of a volatile rubber solvent to the latex and cork filler is also advantageous since it reduces the amount of latex required for a given amount of cork and results in a filler which is more flexible after it has become set.

As hereinafter used the term latex is intended to cover not only natural latices, with or without modification as described above, but also artificial water dispersed rubber cements, as distinguished from the well-known type of cement in which the rubber is dissolved in a readily volatile organic solvent such as naphtha.

In another aspect the invention comprises a shoe having between its insole andits outsole a bottom filler comprising comminuted solid material rendered plastic by the addition of latex, with or without other materials.

With the above and other objects in view the invention will now be described in connection with the accompanying drawing and pointed out in the claims.

The drawing illustrates a shoe the bottom of' which is provided with a filler in accordance With the present invention. i

in making a bottom filler in accordance with my invention may be varied considerably the following describes the compounding of a typical sample of such filler. Commercial rubber latex having a rubber content of perhaps 40% is added to ground cork and the two are thoroughly mixed so that the latex is diffused throughout the cork, enough of the latex being used to form a doughy mass. The proportions of the ingredients necessary will, of course, vary with variations in the composition of the latex and the fineness of the cork.

If it is desired to form afiller which will be more tacky and will, therefore, stick better to the shoe bottom when freshly applied and before it has had time to set, then a resin soap is made, for example by adding one part of rosin to two parts of concentrated ammonia (specific gravity .880), and is added to the latex before the latter is mixed with the cork.

If a more flexible filler than that just described is desired a volatile rubber solvent may beadded after the latex and cork have been mixed. In order toeliminate fire hazard this solvent should be of a non-inflammable nature such as carbon tetrachloride, cyclohexone, etc. For example, 8 gallons of carbon tetrachloride may be added to a dough consisting of 18 pounds of ground cork into which has been worked 14 poundsof latex. To produce a cheaper product naphtha or benzol may be used in place of the carbon tetrachloride mentioned in the foregoing example, though that, of course, increases the fire risk.

The filler manufactured as above may be packed into cans and kept in that manner until it is to be used.

The accompanying drawing illustrates a Goodyear welt shoe having an upper 2, an insole 4, a

'the cork particles 12, as indicated at 14. In making such a shoe the filler is spread cold on the insole of the shoe after the sole and welt have been stitched to the lasted upper and insole and when the shoe is otherwise ready for the attachment of the outsole.

If desired other suitable comminuted solid material, for example wood fibre or leather I fibre, may be used in place of some or all of the While the proportions of the ingredients used ground cork described above. Other resin soaps than that described above may be also used. The soap may be formed by adding rosin to other alaklis than ammonium, for example to a'soda solution. Other resins such as copal and dammar also may be'used for this purpose, though rosin is entirely satisfactory and much cheaper.

If desired the materials described above may be formed into sheets and dried or allowed to dry, suitably shaped pieces being subsequently died out from the sheet material to be used as sheet bottom filler in the manufacture of shoes.

Having thus described the invention, what I Q65 claim as new and desire to secure by Letters Patent of the United States is:

1. A shoe bottom filler comprising a comminuted solid, a binder of latex and a resin soap in proportions to provide a tacky substance of K0 a degree of plasticity which. permits it to be spread readily by hand throughout the cavity in a shoe bottom.

2. A shoe bottom filler comprising a comminuted solid, a binder of latex, a resin soap and a ii5 volatile rubber solvent in proportions to provide a tacky substance of a degree of plasticity which permits it to be spread readily by hand through out the cavity in a shoe bottom.

3. A shoe bottom fillerv comprising a comminuted solid, a binder of latex, a resin soap and carbon tetrachloride in proportions to provide a tacky substance of a degree of plasticity which permits it tov be spread readily by hand throughout the cavity in a shoe bottom.

4. A shoe bottom filler comprising a comminuted solid, a binder of latex, a resin soap and benzol in proportions to provide a tacky substance of a degree of plasticity which permits it a to be spread readily by hand throughout the 130 cavity in a shoe bottom.

HERBERT BARNETT. 

